1. Field of the Invention
The present invention relates to a field of liquid crystal display techniques. More particularly, the present invention relates to a tape substrate for chip on film structure of a liquid crystal panel, and further relates to a liquid crystal panel.
2. Description of the Prior Art
With the advancement of liquid crystal display techniques, the demand for the quality of various parts in the liquid crystal panel is getting higher.
The traditional technique for chip on film (COF) type of package structures basically adopts the technique of tape automated bonding (TAP) for thermal pressing and packaging of driver chips, and the chips on films are put in roll for packing and delivery. During the use, each COF structure is cut from the tape substrate sequentially, and is electrically connected between transparent circuits on a glass substrate of the liquid crystal panel and a driver circuit board. The glass substrate and the driver circuit board are provided with at least one COF structures therebetween. The broader the size of liquid crystal panel is, the more the number of COF structures will be in use.
Referred to FIG. 1, within the COF structure, the lengthwise direction D2 of the driver chip 11 is perpendicular to the longitudinal direction D1 of the tape substrate 10, and input leads 12 of the tape substrate 10 close to the printed circuit board (PCB) side and input leads 13 close to outer lead bonding (OLB) side of the glass substrate are located in the two opposite sides of the driver chip 11, wherein the input leads 12 and the input leads 13 are arranged in radiating shape mainly along the longitudinal direction D1 of the tape substrate 10.
To exemplify the output leads 13, the output leads 13 are connected to the transparent circuits (not shown in the drawings) on the glass substrate of the liquid crystal panel, the output leads 13 are not only more in wiring number, but also arranged denser in layout. As regards the traditional techniques of the COF, the width of the tape substrate 10 is smaller, about 35 or 48 mm in general, and its specification has been standardized, wherein the width of each COF on the tape substrate 10 cannot be enlarged at will. Moreover, as the size of the liquid crystal panel augments gradually, more pieces of COF are demanded, and each COF has more printed wires, and thus the traditional techniques of COF apparently cannot meet the requirements of denser in lead layout demanded by large-size liquid crystal panels.
Opposite to the output leads 13, the input leads 12 have less in wiring number, and in general has more unused space that are usually removed by etching and punching, to become voids between leads. Apparently, the limited width of COF fails to realize the most space utilization at the side of the input leads 12, which results in huge waste in material cost of the tape substrate 10.
Accordingly, how to settle the issues of the unbalanced wiring density between the input leads 12 side and the output leads 13 side existed in the traditional techniques of COF, the unused space of the tape substrate 10 that are not well utilized, and especially the voids between the input leads 12 that result in the material cost waste for the tape substrate 10, are one of the technical problems of the liquid crystal display that need to be settled.